Conversational understanding systems interpret the intent of users and execute actions based on that interpretation. There are various modules involved in conversational understanding processing including speech recognition, domain detection, intent determination, entity extraction, belief state update and policy execution. At every step, there is a possibility that a system can make an unrecoverable mistake and the effect of that mistake gets cascaded throughout the rest of the system. It is with respect to this general technical environment that the present application is directed.